It is well known to draw wire to a fine diameter by sequentially passing the wire through drawing dies, so that the diameter and the cross section of the wire are reduced in steps.
The referenced U.S. Pat. No. 4,366,695 describes, for example, a wire drawing system in which a cold wire is coated with a liquid lubricant, especially a water-graphite suspension. This lubricant must dry before the wire reaches the dies. To reduce wear, the wire is then heated so that it reaches an optimum working temperature at the die. This temperature may vary between about 450.degree. C. to 800.degree. C., in dependence on drawing speed.
Coating can be done by passing the wire through a container filled with lubricant, as described, for example, in U.S. Pat. No. 3,262,293, MacInnis; as an alternative, lubricant can be sprayed on the wire by projecting lubricant from a nozzle, see for example, the referenced German Patent Publication DE 30 48 980, Weinhold et al.
It has been found that these processes have some disadvantages in that the quantity of lubricant applied to the wire, with a given operating or running speed of the wire, can be controlled only by controlling the viscosity of the lubricant. The quantity of lubricant per surface of the wire increases undesirably upon increase of drawing speed. It may occur that the drying time is thereby increased undesirably, so that optimum operating temperatures at the drawing die will no longer be reached. These constraints limited the maximum drawing speed to about 75 m/min., when it is desired to reach a wire diameter of 0.090 mm.